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selinux: use setcon() instead of reexec to apply selinux policy

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This commit is contained in:
Lennart Poettering 2011-07-28 23:52:23 +02:00
parent 058dc6f379
commit 0b3325e79e
5 changed files with 89 additions and 43 deletions
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46
src/main.c
View file

@ -1020,6 +1020,9 @@ int main(int argc, char *argv[]) {
const char *shutdown_verb = NULL;
dual_timestamp initrd_timestamp = { 0ULL, 0ULL };
char systemd[] = "systemd";
bool is_reexec = false;
int j;
bool loaded_policy = false;
#ifdef HAVE_SYSV_COMPAT
if (getpid() != 1 && strstr(program_invocation_short_name, "init")) {
@ -1033,6 +1036,16 @@ int main(int argc, char *argv[]) {
}
#endif
/* Determine if this is a reexecution or normal bootup. We do
* the full command line parsing much later, so let's just
* have a quick peek here. */
for (j = 1; j < argc; j++)
if (streq(argv[j], "--deserialize")) {
break;
is_reexec = true;
}
/* If we get started via the /sbin/init symlink then we are
called 'init'. After a subsequent reexecution we are then
called 'systemd'. That is confusing, hence let's call us
@ -1050,25 +1063,26 @@ int main(int argc, char *argv[]) {
if (getpid() == 1) {
arg_running_as = MANAGER_SYSTEM;
log_set_target(detect_container(NULL) > 0 ? LOG_TARGET_CONSOLE : LOG_TARGET_SYSLOG_OR_KMSG);
log_open();
/* This might actually not return, but cause a
* reexecution */
if (selinux_setup(argv) < 0)
goto finish;
if (!is_reexec)
if (selinux_setup(&loaded_policy) < 0)
goto finish;
log_open();
if (label_init() < 0)
goto finish;
if (hwclock_is_localtime() > 0) {
int err, min;
if (!is_reexec)
if (hwclock_is_localtime() > 0) {
int min;
err = hwclock_apply_localtime_delta(&min);
if (err < 0)
log_error("Failed to apply local time delta: %s", strerror(-err));
else
log_info("RTC configured in localtime, applying delta of %i minutes to system time.", min);
}
r = hwclock_apply_localtime_delta(&min);
if (r < 0)
log_error("Failed to apply local time delta, ignoring: %s", strerror(-r));
else
log_info("RTC configured in localtime, applying delta of %i minutes to system time.", min);
}
} else {
arg_running_as = MANAGER_USER;
@ -1082,7 +1096,7 @@ int main(int argc, char *argv[]) {
/* Mount /proc, /sys and friends, so that /proc/cmdline and
* /proc/$PID/fd is available. */
if (geteuid() == 0 && !getenv("SYSTEMD_SKIP_API_MOUNTS"))
if (mount_setup() < 0)
if (mount_setup(loaded_policy) < 0)
goto finish;
/* Reset all signal handlers. */
@ -1179,7 +1193,7 @@ int main(int argc, char *argv[]) {
/* Reset the console, but only if this is really init and we
* are freshly booted */
if (arg_running_as == MANAGER_SYSTEM && arg_action == ACTION_RUN) {
console_setup(getpid() == 1 && !serialization);
console_setup(getpid() == 1 && !is_reexec);
make_null_stdio();
}
@ -1194,7 +1208,7 @@ int main(int argc, char *argv[]) {
log_full(arg_running_as == MANAGER_SYSTEM ? LOG_INFO : LOG_DEBUG,
PACKAGE_STRING " running in %s mode. (" SYSTEMD_FEATURES "; " DISTRIBUTION ")", manager_running_as_to_string(arg_running_as));
if (arg_running_as == MANAGER_SYSTEM && !serialization) {
if (arg_running_as == MANAGER_SYSTEM && !is_reexec) {
locale_setup();
if (arg_show_status || plymouth_running())

15
src/mount-setup.c
View file

@ -226,7 +226,7 @@ static int nftw_cb(
return 0;
};
int mount_setup(void) {
int mount_setup(bool loaded_policy) {
const char symlinks[] =
"/proc/kcore\0" "/dev/core\0"
@ -247,9 +247,20 @@ int mount_setup(void) {
* the appropriate labels, after mounting. The other virtual
* API file systems like /sys and /proc do not need that, they
* use the same label for all their files. */
if (unlink("/dev/.systemd-relabel-run-dev") >= 0) {
if (loaded_policy) {
usec_t before_relabel, after_relabel;
char timespan[FORMAT_TIMESPAN_MAX];
before_relabel = now(CLOCK_MONOTONIC);
nftw("/dev", nftw_cb, 64, FTW_MOUNT|FTW_PHYS);
nftw("/run", nftw_cb, 64, FTW_MOUNT|FTW_PHYS);
after_relabel = now(CLOCK_MONOTONIC);
log_info("Relabelled /dev and /run in %s.",
format_timespan(timespan, sizeof(timespan), after_relabel - before_relabel));
}
/* Create a few default symlinks, which are normally created

2
src/mount-setup.h
View file

@ -24,7 +24,7 @@
#include <stdbool.h>
int mount_setup(void);
int mount_setup(bool loaded_policy);
bool mount_point_is_api(const char *path);
bool mount_point_ignore(const char *path);

65
src/selinux-setup.c
View file

@ -33,15 +33,21 @@
#include "macro.h"
#include "util.h"
#include "log.h"
#include "label.h"
int selinux_setup(bool *loaded_policy) {
int selinux_setup(char *const argv[]) {
#ifdef HAVE_SELINUX
int enforce = 0;
usec_t n;
usec_t before_load, after_load;
security_context_t con;
int r;
/* Already initialized? */
if (getcon_raw(&con) == 0) {
assert(loaded_policy);
/* Already initialized by somebody else? */
r = getcon_raw(&con);
if (r == 0) {
bool initialized;
initialized = !streq(con, "kernel");
@ -51,33 +57,46 @@ int selinux_setup(char *const argv[]) {
return 0;
}
/* Before we load the policy we create a flag file to ensure
* that after the reexec we iterate through /run and /dev to
* relabel things. */
touch("/dev/.systemd-relabel-run-dev");
/* Make sure we have no fds open while loading the policy and
* transitioning */
log_close();
n = now(CLOCK_MONOTONIC);
if (selinux_init_load_policy(&enforce) == 0) {
char buf[FORMAT_TIMESPAN_MAX];
/* Now load the policy */
before_load = now(CLOCK_MONOTONIC);
r = selinux_init_load_policy(&enforce);
n = now(CLOCK_MONOTONIC) - n;
log_info("Successfully loaded SELinux policy in %s, reexecuting.",
format_timespan(buf, sizeof(buf), n));
if (r == 0) {
char timespan[FORMAT_TIMESPAN_MAX];
char *label;
/* FIXME: Ideally we'd just call setcon() here instead
* of having to reexecute ourselves here. */
/* Transition to the new context */
r = label_get_create_label_from_exe(SYSTEMD_BINARY_PATH, &label);
if (r < 0) {
log_open();
log_error("Failed to compute init label, ignoring.");
} else {
r = setcon(label);
execv(SYSTEMD_BINARY_PATH, argv);
log_error("Failed to reexecute: %m");
return -errno;
log_open();
if (r < 0)
log_error("Failed to transition into init label '%s', ignoring.", label);
label_free(label);
}
after_load = now(CLOCK_MONOTONIC);
log_info("Successfully loaded SELinux policy in %s.",
format_timespan(timespan, sizeof(timespan), after_load - before_load));
*loaded_policy = true;
} else {
unlink("/dev/.systemd-relabel-run-dev");
if (enforce > 0) {
log_full(LOG_ERR, "Failed to load SELinux policy.");
log_error("Failed to load SELinux policy.");
return -EIO;
}
} else
log_debug("Unable to load SELinux policy.");
}
#endif

4
src/selinux-setup.h
View file

@ -22,6 +22,8 @@
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
int selinux_setup(char *const argv[]);
#include <stdbool.h>
int selinux_setup(bool *loaded_policy);
#endif